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Topic:Veterinary Research
Veterinary research in horses encompasses the study of diseases, health management, and medical treatments specific to equine species. This field investigates various aspects of horse health, including infectious diseases, metabolic disorders, and musculoskeletal conditions. Researchers focus on understanding the pathophysiology of equine ailments, developing diagnostic tools, and evaluating therapeutic interventions. The study of horse health also involves examining preventive measures such as vaccination protocols and nutritional management to promote overall well-being. This page collects peer-reviewed research studies and scholarly articles that explore the diverse areas of veterinary science related to horses, providing insights into disease mechanisms, treatment strategies, and advancements in equine healthcare.
Immunization against gnRH in mature mares: antibody titres, ovarian function, hormonal levels and oestrous behaviour. The aim of the present study was to investigate the effect of active immunization against GnRH in mature Standardbred mares (three experimental and one control mare) on antibody titres, ovarian function, hormonal levels and oestrous behaviour. The mares were individually teased with a stallion once each day. During the first part of the experiment (period I: late April until November), blood was sampled every third day during the first 3 months, thereafter once per week. In the second part of the experiment (period II: December until August), sampling was carried out every second week. Progest...
Control of expression of major histocompatibility complex genes in horse trophoblast. In most mammals, the fetus limits its presentation of paternal antigens to the mother by suppressing the cell-surface expression of proteins of the major histocompatibility complex (MHC) on trophoblast. In the horse, however, functional, polymorphic MHC class I antigens are expressed at high levels on the invasive trophoblast cells of the chorionic girdle between Days 32 and 36 of pregnancy, although not on the adjacent noninvasive trophoblast of the chorion and allantochorion membranes. In this study, the control of MHC class I gene expression was investigated in invasive and noninvasive hors...
A simple random amplified polymorphic DNA genotyping method for field isolates of Dermatophilus congolensis. Dermatophilus congolensis is the pathogenic actinomycete that causes dermatophilosis in cattle, lumpy wool in sheep and rain scald in horses. Phenotypic variation between isolates has previously been described, but its genetic basis, extent and importance have not been investigated. Standard DNA extraction methods are not always successful for D. congolensis due to its complex life cycle, one stage of which is encapsulated. Here we describe the development of rapid and reliable DNA extraction and random amplified polymorphic DNA (RAPD) methods that can be used for genotyping D. congolensis fie...
Effect of follicle size on in vitro production of steroids and insulin-like growth factor (IGF)-I, IGF-II, and the IGF-binding proteins by equine ovarian granulosa cells. Little is known regarding the hormonal regulation of granulosa cell steroidogenesis and the ovarian insulin-like growth factor (IGF) system in the mare. The objectives of this study were to determine, first, if estradiol, insulin, and/or FSH affect steroid production by equine granulosa cells (experiment 1) and, second, if the components of the IGF system are produced by equine granulosa cells in culture as well as whether estradiol, insulin, and/or FSH affects IGF and/or IGF-binding protein (IGFBP) production by equine granulosa cells (experiment 2). Granulosa cells from small (6-15 mm), medi...
Full-length complementary DNA and the derived amino acid sequence of horse uteroglobin. After its original description as a steroid-dependent protein in the rabbit uterus, uteroglobin became one of the best characterized proteins. However, detailed knowledge of its physiological role remains an enigma. In this study we investigate how its structure is phylogenetically conserved in the horse compared to other mammalian species. Northern blot analysis showed that in horses, the main expression of uteroglobin appears in lung, uterus, and prostate tissues. Western blot analysis demonstrated that the dimeric form of uteroglobin is found predominantly in biological compartments. Using ...
Effect of time of oocyte collection and site of insemination on oocyte transfer in mares. The objective of the study was to compare embryo development rates after transfer of oocytes collected 22 or 33 h after hCG injection into recipients inseminated within the uterus or the oviduct. Oocytes were collected at approximately 22 or 33 h after hCG injections and incubated for approximately 16 or 1.5 h, respectively, before transfer. Intrauterine inseminations using 1 x 10(9) progressively motile sperm were done approximately 12 h before and 2 h after transfer. For intraoviductal inseminations (gamete intrafallopian transfer [GIFT]), semen was centrifuged through a Percoll gradient, an...
Seroepidemiologic studies on Babesia caballi and Babesia equi infections in Japan. Antibodies to Babesia caballi and Babesia equi were examined on a total of 2,019 horse serum samples that had been collected in 1971-1973 by the National Institute of Animal Health by enzyme-linked immunosorbent assay (ELISA) using recombinant proteins and by Western-blot analysis. Based on the criterion for positivity by ELISA, 5.4% (109/2,019) and 2.2% (44/2,019) had antibodies against B. caballi and B. equi, respectively. The ELISA-positive sera were further examined by Western blot; 30/109 for B. caballi and 2/ 44 for B. equi were positive for native B. caballi or B. equi, but none of them...
Effectiveness of glyceryl trinitrate for enhancing digital submural perfusion in horses. To evaluate the clinical efficacy of topically administered glyceryl trinitrate (GTN) for inducing digital submural vasodilation in clinically normal horses. Methods: 7 adult horses without foot abnormalities. Methods: A concurrent-control crossover design was used to determine whether topical application of GTN ointment for prevention or treatment of laminitis would result in a detectable increase in digital perfusion. Heat-acclimated horses instumented for detection of wall surface temperature (HWST), mean systemic pressure, and heart rate were used. Horses were exposed to cold to induce dig...
Effects of continuous intra-articular infusion of gentamicin on synovial membrane and articular cartilage in the tarsocrural joint of horses. To determine the effects of a continuous intra-articular infusion of gentamicin on the synovial membrane and articular cartilage in the tarsocrural joint of horses. Methods: 6 healthy adult horses. Methods: A balloon infusion system attached to a catheter placed in the plantarolateral pouch of both tarsocrural joints in each horse was used for continuous gentamicin solution (GM) or balanced electrolyte solution (BES) delivery for 5 days. Cartilage and synovial membrane specimens were collected on day 5 from 3 horses and on day 14 from the remaining 3 horses. Both infused joints from each horse...
Effect of hydrochloric acid, pepsin, or taurocholate on bioelectric properties of gastric squamous mucosa in horses. To determine the effect of pH with or without pepsin or taurocholic acid on the bioelectric properties of gastric squamous mucosa in horses. Methods: Gastric tissues obtained from 16 adult horses that did not have evidence of gastric disease. Methods: Bioelectric properties of squamous mucosa were determined, using modified Ussing chambers. Tissues then were exposed to mucosal pepsin (1 mg/ml) or taurocholic acid (2.5 mM) under neutral (pH 74) or acidic (pH 1.7) conditions. Results: Exposure of mucosal sheets to an acidic pH resulted in an immediate and sustained decrease in transmembrane pote...
Metastatic lymphangiosarcoma in a horse. A lymphangiosarcoma with metastases was found in a horse that presented with respiratory distress and edema in the ventral thorax and abdomen. The necropsy revealed diffuse edema in the subcutaneous connective tissue. Mediastinal, mesenteric, iliac, and renal lymph nodes were enlarged and white with soft, yellowish necrotic areas. Histologic examination revealed numerous channels and disorganized vessels lined by large polyhedral, polymorphic cells. Tumor metastases were observed in the spleen, lungs, and kidneys. Immunohistochemical evaluation of the tumor cells demonstrated positive staining...
Plasma disposition, faecal excretion and in vitro metabolism of oxibendazole following oral administration in horses. Oxibendazole (OBZ) was administered to eight horses at an oral dose of 10 mg kg(-1) bodyweight each. Parent OBZ could only be detected in plasma at the 0.5 and 1.0 hours post administration sampling times and the mean maximum plasma concentration was 0.008 microg ml(-1). Parent OBZ was detected in faeces between 12 and 72 hours after administration and the highest dry faecal concentration was detected at 24 hours. An unidentified metabolite was detected in plasma between 0.5 and 72 hours. The unidentified metabolite in the plasma of treated horses corresponded to the second eluted metabolite i...
Identification and distribution of a novel Malassezia species yeast on normal equine skin. This study aimed to investigate the distribution of Malassezia species yeasts on the skin of healthy horses. Acetate tape samples were obtained from the lip, axilla, interbulbar region, groin and anus of 12 healthy horses. The samples were stained and examined microscopically and sites harbouring yeast-like organisms were identified. Contact plates were applied to the skin at these sites and cultured at 26 degrees C and 32 degrees C. No growth was obtained on horse blood, Sabouraud's dextrose or modified Dixon's agar. A pure growth of a Malassezia-type organism was obtained on Sabouraud's dext...
Equine placentation. A tough, elastic glycoprotein capsule envelops the equine blastocyst between Days 6 and 23 after ovulation. It maintains the spherical configuration of, and provides physical support for, the embryo as it traverses the entire uterine lumen during Days 6-17, propelled by myometrial contractions that are stimulated by pulsatile release of prostaglandin F2alpha and prostaglandin E2. The capsule also accumulates constituents of the exocrine secretions of the endometrial glands ('uterine milk') as nutrients for the mobile embryo as it releases its antiluteolytic maternal recognition-of-pregnancy si...
Isolation and species distribution of staphylococci from animal and human skin. From April 1999 to December 2000, a survey was made on the distribution of Staphylococcus species on the skin of 7 kinds of animals and humans. Staphylococci were isolated from 12 (100%) of 12 pigs, 17 (89.5%) of 19 horses, 30 (100%) of 30 cows, 73 (90.1%) of 81 chickens, 10 (40%) of 25 dogs, 23 (76.7%) of 30 laboratory mice, 20 (52.6%) of 38 pigeons, and 80 (88.9%) of 90 human beings. The predominant staphylococci isolated from a variety of animal species were novobiocin-resistant species, S. xylosus and S. sciuri regardless of the animal host species. The novobiocin-resistant species includi...
The equine hypophysis: a gland for all seasons. The intrahypophysial mechanisms involved in the control of gonadotrophin secretion remain unclear. In the horse, a divergent pattern of gonadotrophins is observed at different stages of the reproductive cycle in response to a single secretagogue (gonadotrophin-releasing hormone), and dramatic changes in fertility take place throughout the year in response to photoperiod. This species thus provides a useful model to investigate the regulation of fertility directly at the level of the hypophysis. A series of studies were undertaken to examine the cytological arrangements and heterogeneity of gon...
Preliminary observations on expression of transforming growth factors beta1 and beta3 in equine full-thickness skin wounds healing normally or with exuberant granulation tissue. To determine whether transforming growth factor (TGF)-beta1 and -beta3 expression differs between equine limb wounds healing normally and those healing with experimentally induced exuberant granulation tissue (EGT). Methods: Six wounds were created on the lateral aspect of both metacarpi of each horse; one forelimb was untreated, and the other was bandaged to stimulate the development of EGT. Sequential wound biopsies allowed comparison of growth factor expression between the two types of wound. Methods: Four horses (2 to 4 years of age; 350 to 420 kg). Methods: Wounds were assessed grossly, h...
An in vitro biomechanical investigation of an MP35N intramedullary interlocking nail system for repair of third metacarpal fractures in adult horses. To compare monotonic mechanical properties of gap-ostectomized third metacarpal bones (MC3) stabilized with an MP35N interlocking nail system with contralateral intact bones. Methods: Twenty-four pairs of cadaveric equine MC3s. Methods: Third metacarpal bones were divided into 4 mechanical testing groups (6 pairs per group): compression, palmarodorsal (PD) and mediolateral (ML) 4-point bending, and torsion. One MC3 from each pair was randomly selected as an intact specimen, and the contralateral gap ostectomized bone was stabilized with a 4-hole, 14-mm-diameter, 250-mm-long, MP35N intramedulla...
A biomechanical comparison of equine third metacarpal condylar bone fragment compression and screw pushout strength between headless tapered variable pitch and AO cortical bone screws. To compare bone fragment compression and the mechanical pushout strength and stiffness of 6.5-mm Acutrak Plus (AP) and 4.5-mm AO cortical (AO) bone screws after stabilization of a simulated equine third metacarpal (MC3) bone complete lateral condylar fracture. Methods: In vitro biomechanical paired study of screw insertion variables, bone fragment compression, and screw pushout tests using a bone screw stabilized simulated lateral condylar fracture model. Methods: Six pairs of cadaveric equine MC3s. Methods: Metacarpi were placed in a fixture and centered on a biaxial load cell in a materials ...
Temporal localization of immunoreactive transforming growth factor beta1 in normal equine skin and in full-thickness dermal wounds. To describe the localization of immunoreactive transforming growth factor (TGF)-beta1 in both normal skin and full-thickness dermal wounds of the limb and the thorax of the horse. Methods: Six full-thickness excisional wounds were created on the lateral aspect of one metacarpal region and on the midthoracic area of each horse. Sequentially collected tissue specimens from wound margins were assessed for TGF-beta1 expression by immunohistochemistry. Methods: Four horses (2 to 4 years of age). Methods: A neutralizing monoclonal anti-human TGF-beta1 antibody was used to detect the spatial expressi...
Comparison of insertion time and pullout strength between self-tapping and non-self-tapping AO 4.5-mm cortical bone screws in adult equine third metacarpal bone. To compare screw insertion characteristics and pullout mechanical properties between self-tapping (ST) and non-self-tapping (NST) AO 4.5-mm cortical bone screws in adult equine third metacarpal bone (MC3). Methods: In vitro biomechanical experiment. Methods: Seven pairs of adult equine MC3. Methods: Bicortical holes were drilled transversely in proximal metaphyseal, diaphyseal, and distal metaphyseal locations of paired MC3. NST screws were inserted in pre-tapped holes in 3 sites of one bone pair, and ST screws were inserted in non-tapped holes of contralateral MC3. Tapping and screw insertion...
Some morphological aspects of Cylicocyclus brevicapsulatus (Nematoda: Cyathostominae) parasite of horse. This paper describes some morphological aspects of Cylicocyclus brevicapsulatus (Ihle, 1920) (Nematoda: Cyathostominae) from Equus caballus in Brazil. The worms were studied using an optical microscope (measurements and illustrations) and a scanning electron microscope for a more detailed examination of the external morphology. The buccal capsule is very short, with a very thin wall, and the dorsal gutter is absent. Other morphological aspects are described including measurement of the spicules and gubernaculum.
Effect of different pulses of nitric oxide on venous admixture in the anaesthetized horse. Dependent atelectatic lung areas open towards the end of inspiration when the lung opening pressure increases, and recollapse during expiration. We hypothesized that inhaled nitric oxide (NO) counteracts hypoxic vasoconstriction in these collapsing lung areas, resulting in increased pulmonary shunt perfusion. Methods: We administered NO as a pulse and varied the pulse timing during inspiration in equine anaesthesia, where atelectasis develops regularly. Six spontaneously breathing standard breed trotters were studied under isoflurane anaesthesia in lateral recumbency. NO pulsed into the first ...
Survey of complications and antimicrobial use in equine patients at veterinary teaching hospitals that underwent surgery because of colic. To determine current practices regarding use of antimicrobials in equine patients undergoing surgery because of colic at veterinary teaching hospitals. Methods: Survey. Methods: Diplomates of the American College of Veterinary Surgeons performing equine surgery at veterinary teaching hospitals in the United States. Methods: A Web-based questionnaire was developed, and 85 surgeons were asked to participate. The first part of the survey requested demographic information and information about total number of colic surgeries performed at the hospital, number of colic surgeries performed by the res...
Contractile response of horse deep dorsal penile vein to histamine. The present investigation was designed to evaluate the effect of histamine on isolated rings of horse deep dorsal penile vein. Under precontracted or basal conditions, histamine evoked an endothelium-independent contraction. Preincubation of the vein rings with the selective H1 receptor antagonist, mepyramine, shifted the concentration-response curve for histamine and to the H1 receptor agonist 2-pyridylethylamine to the right in a competitive manner. Pretreatment with cimetidine, a specific H2 receptor antagonist, did not modify the pEC50 and maximal contraction of the histamine response. Cim...
Comparison, characterization, and identification of proteases and protease inhibitors in epididymal fluids of domestic mammals. Matrix metalloproteinases are major fluid gelatinases. The testicular and epididymal fluids of ram, boar, and stallion were analyzed by means of one-dimensional and two-dimensional gelatin gel zymography. Five main gelatinolytic bands were revealed in the ram and at least seven were observed in the boar and stallion. These proteolytic bands showed regionalized distribution throughout the organs. The two main proteolytic activities at around 54-66 kDa retrieved in all three species were inhibited by EDTA and phenanthroline, indicating that they were metallo-dependent enzymes. The activity of some of the low-molecular-weight gelatinases was also dec...
In vitro development of horse oocytes reconstructed with the nuclei of fetal and adult cells. This study investigated the basic conditions required for the production of horse embryos by the transfer of the nuclei of fetal and adult fibroblast cells to enucleated oocytes. Cumulus-oocyte complexes were recovered from abattoir ovaries and matured in vitro in groups of 20-30 for 28-30 h in tissue culture medium 199 containing 20% v:v fetal bovine serum in coculture with equine oviduct epithelial cells. Fetal fibroblast cells (FFC) were derived from a 32-day-old Thoroughbred x Pony fetus, and adult skin fibroblast cells (SFC) were obtained from subdermal biopsies recovered from a 4-yr-old ...
